Improvement in squares



J. c. MARSHALL.

SQUARES. No.185,830. Patented Jan.2,1877.

N PETQRS, PHOTQLITHOGRAFNER. WASHINGTON D C which the blade passes.

.UNITED STATES PATENT ()FFIGE.

JOSEPH OJMARSHALL, OF SPRINGFIELD, MASSACHUSETTS.

IMPROVEMENT IN SQUARES.

Specification forming part of Letters Patent No. 185,830, dated January2, 1877; application filed August 28, 1876.

To all whom it may concern:

Be it known that I, JOSEPH O. MARSHALL, of Springfield, in the county ofHampden, State of Massachusetts, have invented a new and usefulImprovementin Squares, and that the following is a full, clear, andexact description thereof, reference being bad to the acc0mpanyingdrawings, making a part of this specification.

My improvement consists in attaching to the head or beam of the square ablade which can be moved radially or longitudinally on the pivotal bolt,or can be removed from the head and used as a scale.

Figure l is a plan view of my invention, showing the blade in contactwith the shoulder E and the projection D. Fig. 2 is a plan view of thesame, showing the blade moved longitudinally and from the shoulder E andprojection D on the pivotal bolt which secures it to the head.

In the drawing, A represents the head or beam with its angular arms,which project at an equal angle with the face of the head, but

in opposite directions. This angle is preferably forty-five degrees, inwhich case the faces of the two arms would form an angle of ninetydegrees. B represents the graduated blade, which is attached to the headby the bolt 0, which is made with a slot in the head, through Drepresents a pro jection on the side of the head, the face of which iscoincident with the juncture of the faces of the angular arms. Erepresents a shoulder in the head the width of the blade, above the faceof the projection D, so that when the blade is in position, with itslower edge in contact with the projection D, and its upper edge is incontact with the shoulder E, it will form an equal angle with theangular arms and a right angle with the face of the head.

The advantages of my invention are as follows: It can be used as asquare of any length of blade. It can be used as a center-square forfinding the center of.circular work; also, by shortening the blade,radial lines can be drawn on circular work where there is a hub or otherprojection. It can also be used as a bevel, and to draw ratchet-teeth,&c., on circular Work, and the blade, being detached, can be used as anordinary scale.

I claim- The head having arms at an equal angle with its base, andprovided with the projection l) and shoulder E, in combination with theslotted headed bolt and movable blade, substantially as described.

JOSEPH CLINTON MARSHALL.

Witnesses:

H. M. OONKEY, CHARLES C. MARSHALL.

